PNW 548 June 2001 Fall and Winter Vegetable Gardening in the Pacific Northwest Oregon State University + University of Idaho L Washington State University Fall and Winter Gardening in the Pacific Northwest P. Patterson ith a little extra planning and care, you can enjoy fresh vegetables from your garden most of the year. Many cool-season crops produce well in the fall and, in mild-winter W areas of the Pacific Northwest, hold through the winter if protected. You can plant these vegetables in mid- to late summer after you harvest spring crops and as space is available. To be successful, you need to plan ahead, choose varieties wisely, and give proper care to your plants. Keep in mind that fall and winter weather can vary greatly from year to year. A crop that fails one year due to an unusually early freeze or an abnormally cold winter might thrive in a milder year. Be willing to experiment, and don’t give up if your results some years are less than ideal. GETTING STARTED Choosing varieties all gardening is possible in most parts of the Pacific Northwest. Late plantings of warm- Fseason crops such as corn and beans can be harvested until the first killing frost. Cool-season crops, such as kale, turnips, mustard, broccoli, and cabbage, withstand frost and grow well during cool fall days. In fact, some of the best vegetables are produced during the warm days and cool nights of fall. These environmental conditions add sugar to sweet corn and crispness to carrots. Parsnips, kale, collards, Brussels sprouts, and Jerusalem artichokes are examples of crops that are improved by a touch of frost. Winter gardening is possible in mild-winter areas west of the Cascades. With a little protection, cool-weather crops can be harvested throughout the winter. In addition, some fall- planted crops (for example, certain varieties of broccoli, carrots, and onions) will grow slowly through the winter and be ready to harvest early in the spring. Choose varieties that are suited to fall and winter harvest. Some varieties are designated specifically for fall planting, while others perform well only in the spring. Table 1 lists some good varietal selections for several vegetables that are appropriate for fall and winter gardens. Consult seed catalogs for additional information. Pat Patterson, Extension program assistant (home horticulture), Lane County, Oregon State University 2 Table 1.—Vegetables for fall and winter gardening Minimum Start well Store Early spring Recommended Crop temperature (°F) ahead in garden* harvest varieties/Comments Beet 15 •• •Winterkeeper, Albina Verduna. Will resprout in spring for greens. Broccoli 10 • Purple Sprouting, White Sprouting Late, Rudolph Brussels sprouts 10 • Jade Cross “E”, Lunet, Oliver, Red Rubine Cabbage 10 •• •Danish Ballhead, Excel, Gloria, Melissa, Zerlina Carrot 15 • Bolero, Merida, Royal Chantenay Cauliflower 10 • Snow Crown, Snow Ball Celeriac 20 Can go to 10°F if cloched. Celery 10 ••Utah Improved. Needs some protection. Celtuce 20 Can go to 10°F if cloched. Chives 0 • Collard 0 • Champion Corn salad, 0 • Use small-leaf varieties. fetticus, feldsalat, lambs’ lettuce Cress, winter 15 Endive 10 President, Perfect. Best under cloche. Fava bean 15 Aquadulce, Sweet Lorane for eating. Plant September– August for May harvest. Many varieties are even hardier. Fennel 20 Can go to 10°F if cloched. Self-sows freely. Garlic 0 • Mulch. Horseradish 0 • Restrict spread! Jerusalem artichoke 0 •• Restrict spread! Kale 0 • Winter Red, Winterbor, Siberian Kohlrabi 15 • Grand Duke, Kongo, Winner Leek 0 •• Durabel, Alaska, Goliath, Siberia, Mekwina Lettuce, leaf 15 • Winter Density, Oak Leaf, Top Gun, Merveille des Quatre Saisons (also known as Continuity). Best under cloche to prevent rain damage. Mustard 20 • Mizuna. Can go to 10°F if cloched. Onion 0 • Bulbs: Walla Walla, Keepwell, Hi-Ball, Buffalo, Red Cross. Bulblets and tops: Egyptian Top, Multiplier. Scallions: Hardy white bunching (Scallions usually are better in spring.) Parsley 0 • Italian plain leaf; curled types with some protection. Parsnip 0 •• Cobham Marrow, Gladiator Radish, Oriental 10 ••All Season’s White Long, China Rose Rutabaga 20 • Marian, American Purple Top, Improved Laurentian. Can go to 10°F if cloched. Salsify 0 •• Spinach 0 • Bloomsdale Savoy, Tyee, Skookum, Olympia, Hybrid 424, Melody, Wolter Baker, St. Helens. Plant in well-drained soil. Swiss chard 10 • Perpetual, Dorat, Ruby Red. Even spring-planted chard often comes through the winter and resprouts. Turnip 10 • Purple Top White Globe. Also good for late fall harvest. *Mature vegetables can be stored in the ground and used as needed. 3 Choosing a location he first key to a successful fall or winter garden is location. Much depends on your garden’s Tmicroclimate. Microclimates vary from yard to yard (for example, urban gardens tend to be warmer than rural gardens) and within a single yard. Choose the warmest location you have. Don’t plant in a spot that is prone to early frost (for example, at the bottom of a hill) or exposed to the wind. Look for an area that gets as much sun as possible during the short days of autumn and winter, such as a south-facing slope. If possible, place your garden where it is easily accessible. It’s no fun to slog through winter’s mud and cold rain to harvest your crops. To reduce insect and disease problems, don’t plant crops where a related vegetable was growing. For example, put broccoli in a spot vacated by peas, not by cabbage. See OSU Extension publication FS 242, Preventing Plant Disease in Your Garden and Landscape (“For more information,” page 8). Preparing the soil or crops that will be in the garden during the rainy season, good drainage is essential. Raised Fbeds are best. If your soil doesn’t drain well, amend it with organic matter such as compost. Prepare the soil by restoring nutrients removed by spring and summer crops. A light layer of compost or aged manure, or a small application of a complete chemical or organic fertilizer, boosts soil nutrients in preparation for another crop. PLANTING AND EARLY CARE When to plant for fall harvest imely planting is another key to a successful fall garden. The crops need time to mature Tbefore cold weather and short days curtail growth; but, if you plant too early, the young plants might wilt in the heat or mature too soon. To determine the time to plant a particular vegetable for the latest harvest, you need to know the average date of the first killing frost in your area and the number of days to maturity for the variety grown. Choose the fastest maturing varieties for late plantings. The formula below can help you determine when to start your fall garden. Number of days from seeding or transplanting outdoors to harvest + Number of days from seed to transplant (if you grow your own transplants) + Average harvest period + Fall factor (about 2 weeks) + Frost-tender factor (if applicable) = Days to count back from first frost date The fall factor takes into account the fact that plants grow more slowly during the cool, short days of autumn. The frost-tender factor is added only for those crops that are sensitive to frost (e.g., corn, beans, cucumbers, tomatoes, and squash). These crops must mature 2 weeks before frost to produce a reasonable harvest. Presprouting seeds ou can reduce the fall factor by 2 to 5 days by presprouting seeds indoors. Almost any crop Ycan benefit from presprouting. To presprout seeds, place them between two layers of damp paper towels. Place the towels in a plastic bag and keep them in a warm place until the seeds germinate. Another method is to soak seeds for 4 hours. Allow the seedlings to reach a length of up to 1 inch. Be careful not to break the roots when planting. You can plant sprouted seeds more deeply than normal to help prevent drying out. Water well until the plants break the soil surface. 4 When to plant for winter harvest rops that go through the winter in mild areas of the Pacific Northwest must be well Cestablished, but not mature, unless you simply are storing them in the ground (i.e., root vegetables such as carrots and leeks). Most winter crops are planted from June to early August. Table 2 shows recommended planting dates for several winter vegetables. Table 2.—Recommended planting dates for winter vegetables.* Crop Planting date Planting method Beet July 15 Seed Broccoli June Transplant or seed July Brussels sprouts July 10–15 Transplant Cabbage, extra early June Transplant or seed July 15–August 1 Cabbage, late May 20–June 25 Transplant or seed Carrot July 15 Seed Celeriac June Transplant Celery June 1–July 15 Transplant Chinese cabbage July 1–15 Seed Collard July 15 Seed Corn salad September Seed Fava bean September; February 1–March 31 Seed Kale June Transplant or seed July 20–August 10 Kohlrabi June Transplant or seed July 20–August 10 Lettuce, head To July 15 Transplant or seed Lettuce, leaf To August 10 and Transplant or seed December–January Mustard August 15–October 10 Seed Onion, bulbing August 1 Sets Onion, multiplier September Sets Parsnip May 15–June 15 Seed Rutabaga July 10–31 Seed Spinach August 1–15 Transplant or seed Swiss chard June–July Seed Turnip August Seed *Dates recommended are for the mid-Willamette Valley, Oregon. Planting dates might vary in other areas. Early care f it’s hot and sunny when you plant, your young plants will need extra care. Water transplants Idaily at first. You might need to sprinkle seeds and newly germinated seedlings twice a day. To keep the soil moist and protect young plants from the sun, temporarily shade them.